Karel Martens (1939) is a Dutch graphic designer and teacher. His body of work spans over 50 years. His work ranges from post stamps, books, architectural interventions to free artistic work. In 1996 he was awarded the Dr. H.A. Heineken Award.

He taught at the Art Academy in Arnhem, Jan van Eyck Academy in Maastricht (1994-1999), From 1997 he has been a visiting lecturer in the graphic design department at the School of Art, Yale University. In 1997 he started Werkplaats Typografie, a post-graduate graphic design school in Arnhem, where he still teaches.